Even Iran, Syria's best friend, urges Assad to ease crackdown

The shift appears driven not so much by a desire for human rights protections or democratic progress, however – Iran reportedly has helped Syria crack down on the protesters – but rather a concern that a collapse of the Assad regime could result in an "unprecedented regional crisis," according to the Associated Press.

Iran's ties with Syria go far beyond the countries' long-standing friendship in a region dominated by Arab suspicions of Tehran's aims. Syria also is Iran's conduit for aid to powerful anti-Israel proxies Hezbollah in Lebanon and Hamas in the Gaza Strip.

Should Assad's regime fall, it could rob Iran of a loyal Arab partner in a region profoundly realigned by uprisings demanding more freedom and democracy.